The bright green Royal College of Art invitation sits tantalisingly on the mantelpiece. This year’s RCA Secret takes place on November 21 and looks set to be the best yet, with original works by artists like Grayson Perry, Gerhard Richter and Julian Opie on sale.

RCA Secret was launched back in 1994 and is now an annual event.  Each year hundreds of artists, from penniless students to household names, create a one-off work of art on a postcard. The public can then buy one of the 2,000 cards on display for £40 (all proceeds go to support student artists training at the RCA). But the catch is that you don’t know who designed your card till you’ve handed over your money.

The first time round I queued for three and a half hours and failed to buy anything. So the following year we set the alarm for the crack of dawn and arrived at 6.30am. Big mistake. By the time we got to Kensington Gore the queue snaked right round the college and back again. Some intrepid art fans had pitched sub-arctic style tents on the pavement outside and rumours were flying around in the darkness that they’d been there for three days.

We thought we were well-equipped for the wait with coffee, iPods and thermals but our efforts paled into insignificance next to our fellow queuers. Most had sleeping bags, blankets, chairs and ski gear.

When the queue hadn’t moved an inch after 90 minutes my son whispered in my ear. “Shall we go home?” he said. Freezing cold and fed-up, I agreed. But my daughter wasn’t having any of it. “Don’t be so feeble,” she instructed us firmly.

It was an agonising five hours till we got to the front of the queue. By the time we got inside the RCA building we were so numb with cold we could barely speak. And just like the year before, when we made it to the basement saleroom virtually all the cards we liked had gone. Electronic score boards flashed green for cards that were still available, red for ones that had sold. My daughter gave a running commentary as we inched closer and closer to the sales desk. “There’s one of your choices left, and one of mine,” she told us cheerily.

“Numbers 113 and 1898,” she told the saleswoman, when we finally made it to the front. And guess what? They were still there!

“You were right to make us wait,” I said as we trudged out, clutching our precious postcards. “But I’m not coming again next year.”

Except now it’s nearly time for the 2009 event… and I’m wavering.

Find out more at  www.rca.ac.uk/secret